1. Field of the Invention
The disclosures herein generally relate to an image processing apparatus and an image processing method.
2. Description of the Related Art
In recent years, video-conferences between remote locations have become popular in which images and sound are distributed from a terminal to other remote terminals via networks such as the Internet. A terminal used in a video-conference may be provided with a video camera or a mike through which visual or audio data can be captured and transmitted to other terminals at remote locations via networks, which makes it possible to hold a conference between remote locations.
In general, an amount of image data used for moving pictures is large. Moreover, high-quality picture technologies developed in recent years increase workload for image processing operations at terminal devices, which incurs an increased amount of processing time of the image data, sometimes appearing as an increased delay of transmission of the image data.
Examples of image processing operations done at a terminal may include image rotation, cut-out of a designated area, tilt correction, magnification, distortion correction, white balance adjustment, brightness adjustment, etc.
A required amount of data used for an image processing operation and the size of required memory for the data vary from operation to operation. For example, rotation, cut-out, tilt correction, or magnification needs a frame buffer to process a frame of image data at one time. Distortion correction requires a line buffer to process a chunk of several lines of data at one time. White balance adjustment or brightness adjustment does not need a buffer because these operations can be done with sequential processing. To cope with several types of image processing operations, an image processing apparatus provides a frame buffer to fit the largest required amount of data.
An image processing apparatus having a frame buffer executes image processing operations frame by frame. A frame of data is processed after the frame buffer has been filled with lines captured by an imaging device one line at a time. Waiting for the completion of the filling of the frame buffer may result in an increased delay of transmission of the image data. In other words, I/O operations for memory, or the frame buffer, may form a bottleneck of image processing operations.
Japanese Laid-open Patent Publication No. 2010-134743, for example, discloses details.
Conventional image processing apparatuses mentioned above, however, suffer from delays caused by memory write operations to fill one frame with image data, regardless of types of image processing operations.